/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.config.spring;

import org.apache.dubbo.common.Constants;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.ConfigCenterConfig;
import org.apache.dubbo.config.ConsumerConfig;
import org.apache.dubbo.config.MetadataReportConfig;
import org.apache.dubbo.config.ModuleConfig;
import org.apache.dubbo.config.MonitorConfig;
import org.apache.dubbo.config.ReferenceConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.config.annotation.Reference;
import org.apache.dubbo.config.spring.extension.SpringExtensionFactory;
import org.apache.dubbo.config.support.Parameter;

import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

/**
 * ReferenceFactoryBean
 */
public class ReferenceBean<T> extends ReferenceConfig<T> implements FactoryBean,
    ApplicationContextAware, InitializingBean, DisposableBean {

  private static final long serialVersionUID = 213195494150089726L;

  private transient ApplicationContext applicationContext;

  public ReferenceBean() {
    super();
  }

  public ReferenceBean(Reference reference) {
    super(reference);
  }

  @Override
  public void setApplicationContext(ApplicationContext applicationContext) {
    this.applicationContext = applicationContext;
    SpringExtensionFactory.addApplicationContext(applicationContext);
  }

  @Override
  public Object getObject() {
    // 当前ReferenceBean是一个FactoryBean类型的对象，其表征了当前consumer所引用的一个provider服务，
    // 也就是说，最终获取这个对象的方法入口是这里的getObject()
    return get();
  }

  @Override
  public Class<?> getObjectType() {
    return getInterfaceClass();
  }

  @Override
  @Parameter(excluded = true)
  public boolean isSingleton() {
    return true;
  }

  @Override
  @SuppressWarnings({"unchecked"})
  public void afterPropertiesSet() throws Exception {
    if (applicationContext != null) {
      BeanFactoryUtils
          .beansOfTypeIncludingAncestors(applicationContext, ConfigCenterBean.class, false, false);
    }

    if (getConsumer() == null) {
      Map<String, ConsumerConfig> consumerConfigMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, ConsumerConfig.class, false,
                  false);
      if (consumerConfigMap != null && consumerConfigMap.size() > 0) {
        ConsumerConfig consumerConfig = null;
        for (ConsumerConfig config : consumerConfigMap.values()) {
          if (config.isDefault() == null || config.isDefault()) {
            if (consumerConfig != null) {
              throw new IllegalStateException(
                  "Duplicate consumer configs: " + consumerConfig + " and " + config);
            }
            consumerConfig = config;
          }
        }
        if (consumerConfig != null) {
          setConsumer(consumerConfig);
        }
      }
    }
    if (getApplication() == null
        && (getConsumer() == null || getConsumer().getApplication() == null)) {
      Map<String, ApplicationConfig> applicationConfigMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, ApplicationConfig.class, false,
                  false);
      if (applicationConfigMap != null && applicationConfigMap.size() > 0) {
        ApplicationConfig applicationConfig = null;
        for (ApplicationConfig config : applicationConfigMap.values()) {
          if (applicationConfig != null) {
            throw new IllegalStateException(
                "Duplicate application configs: " + applicationConfig + " and " + config);
          }
          applicationConfig = config;
        }
        if (applicationConfig != null) {
          setApplication(applicationConfig);
        }
      }
    }
    if (getModule() == null
        && (getConsumer() == null || getConsumer().getModule() == null)) {
      Map<String, ModuleConfig> moduleConfigMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, ModuleConfig.class, false, false);
      if (moduleConfigMap != null && moduleConfigMap.size() > 0) {
        ModuleConfig moduleConfig = null;
        for (ModuleConfig config : moduleConfigMap.values()) {
          if (config.isDefault() == null || config.isDefault()) {
            if (moduleConfig != null) {
              throw new IllegalStateException(
                  "Duplicate module configs: " + moduleConfig + " and " + config);
            }
            moduleConfig = config;
          }
        }
        if (moduleConfig != null) {
          setModule(moduleConfig);
        }
      }
    }

    if (StringUtils.isEmpty(getRegistryIds())) {
      if (getApplication() != null && StringUtils.isNotEmpty(getApplication().getRegistryIds())) {
        setRegistryIds(getApplication().getRegistryIds());
      }
      if (getConsumer() != null && StringUtils.isNotEmpty(getConsumer().getRegistryIds())) {
        setRegistryIds(getConsumer().getRegistryIds());
      }
    }

    if (CollectionUtils.isEmpty(getRegistries())
        && (getConsumer() == null || CollectionUtils.isEmpty(getConsumer().getRegistries()))
        && (getApplication() == null || CollectionUtils
        .isEmpty(getApplication().getRegistries()))) {
      Map<String, RegistryConfig> registryConfigMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, RegistryConfig.class, false,
                  false);
      if (registryConfigMap != null && registryConfigMap.size() > 0) {
        List<RegistryConfig> registryConfigs = new ArrayList<>();
        if (StringUtils.isNotEmpty(registryIds)) {
          Arrays.stream(Constants.COMMA_SPLIT_PATTERN.split(registryIds)).forEach(id -> {
            if (registryConfigMap.containsKey(id)) {
              registryConfigs.add(registryConfigMap.get(id));
            }
          });
        }

        if (registryConfigs.isEmpty()) {
          for (RegistryConfig config : registryConfigMap.values()) {
            if (StringUtils.isEmpty(registryIds)) {
              registryConfigs.add(config);
            }
          }
        }
        if (!registryConfigs.isEmpty()) {
          super.setRegistries(registryConfigs);
        }
      }
    }

    if (getMetadataReportConfig() == null) {
      Map<String, MetadataReportConfig> metadataReportConfigMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, MetadataReportConfig.class, false,
                  false);
      if (metadataReportConfigMap != null && metadataReportConfigMap.size() == 1) {
        // first elements
        super.setMetadataReportConfig(metadataReportConfigMap.values().iterator().next());
      } else if (metadataReportConfigMap != null && metadataReportConfigMap.size() > 1) {
        throw new IllegalStateException(
            "Multiple MetadataReport configs: " + metadataReportConfigMap);
      }
    }

    if (getConfigCenter() == null) {
      Map<String, ConfigCenterConfig> configenterMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, ConfigCenterConfig.class, false,
                  false);
      if (configenterMap != null && configenterMap.size() == 1) {
        super.setConfigCenter(configenterMap.values().iterator().next());
      } else if (configenterMap != null && configenterMap.size() > 1) {
        throw new IllegalStateException("Multiple ConfigCenter found:" + configenterMap);
      }
    }

    if (getMonitor() == null
        && (getConsumer() == null || getConsumer().getMonitor() == null)
        && (getApplication() == null || getApplication().getMonitor() == null)) {
      Map<String, MonitorConfig> monitorConfigMap = applicationContext == null ? null
          : BeanFactoryUtils
              .beansOfTypeIncludingAncestors(applicationContext, MonitorConfig.class, false, false);
      if (monitorConfigMap != null && monitorConfigMap.size() > 0) {
        MonitorConfig monitorConfig = null;
        for (MonitorConfig config : monitorConfigMap.values()) {
          if (config.isDefault() == null || config.isDefault()) {
            if (monitorConfig != null) {
              throw new IllegalStateException(
                  "Duplicate monitor configs: " + monitorConfig + " and " + config);
            }
            monitorConfig = config;
          }
        }
        if (monitorConfig != null) {
          setMonitor(monitorConfig);
        }
      }
    }

    if (shouldInit()) {
      getObject();
    }
  }

  @Override
  public void destroy() {
    // do nothing
  }
}
